Chronical illness-related LIMitations in the Ability to cope with rising TEmperatures (“CLIMATE Cohort Study”)
Background
Due to climate change, hot days and heat waves occur with increasing frequency. During prolonged periods of heat, people with chronic illnesses are at particular risk of health problems and adverse events such as heatstroke. Empowering people with chronic illnesses to recognize heat-related health risks and act appropriately in such situations is an essential part of protecting the population from adverse effects of heat. For example, individual cooling strategies can reduce physiological heat stress and the associated health risks. There is already a wide range of recommendations from various stakeholders on how to deal with heat. However, potential health benefits of these recommendations have not yet been sufficiently researched under everyday conditions, yet. In particular, there is a lack of data for people with chronic diseases.
The CLIMATE study therefore aims to determine the extent to which patients with chronic diseases experience health problems during hot days, the extent to which these impairments are influenced by psychosocial factors, and the extent to which individual coping strategies for heat can help protect against these health problems.
Procedure
The CLIMATE study is a prospective cohort study of patients with chronic diseases. The study is based on online surveys using a baseline questionnaire and symptom diaries, which are completed on 12 specific observation days, and comprise heat-related symptoms, individual coping strategies for heat, and other variables, such as sociodemographic and psychosocial factors.
The ability to cope with heat is assessed using a self-developed questionnaire. The first version of the questionnaire was based on literature on measuring resilience and on protective factors and measures for preventing the negative effects of heat on the health of individuals with chronic diseases. Between May 2 and 12, 2023, a panel of experts in general medicine, geriatrics, cardiology, diabetology, pulmonology, psychiatry, nephrology, emergency medicine, and climatology then evaluated the items of the questionnaire in terms of one-dimensionality, relevance, influenceability, and evidence base. Reliability and validity of the selected items were verified as part of our study.
The exposure variable in the cohort study was the “heat index,” which is calculated using temperature and humidity data from the nearest meteorological station. In follow-up surveys, patients completed a symptom diary that assessed various complaints that can be influenced by heat, e.g., shortness of breath, circulatory problems, or nausea and vomiting.
The study included all patients with one or more chronic diseases that pose potential health risks due to heat. Exclusion criteria were poor German language skills, lack of capacity to give consent, and functional limitations, e.g., blindness. Eligible patients were invited to participate in the study by cooperating practices. If interested, patients could register online after giving their informed consent and complete the baseline questionnaire. Follow-up surveys took place on both hot and cold days.
The study was piloted between July 24 and September 3, 2023, with 294 observations of 61 patients from 14 practices ( NCT05961163 ). The second wave of the survey, with 4,434 observations of 509 patients from 64 practices, was conducted between May 23 and September 19, 2024 ( NCT06407154 ). A third wave of the survey was conducted between June 11 and September 30, 2025, with 997 observations of 124 patients from 17 practices in Germany and 285 observations of 52 patients from 9 practices in Italy. ( NCT06890208 ).
Expected benefits, expected results
Knowledge about the associated between chronic diseases and protective behavior on the one hand and symptom burden on the other could help GPs to improve their care for chronically ill patients during heat waves. Possible interventions could include patient education for improving health literacy or commissioning a nursing service, for example.
Collaborative partner
Publications
Other projects in this field
Primary care-based interventions addressing Chronic illness-related LIMitations of the Ability to cope with heat and rising Temperatures: a scoping review “CLIMATE Evidence Study”
Chronical illness-related LIMitations in the Ability to cope with rising Temperatures: a qualitative study “CLIMATE Exploration Study ”
Funding: Federal Ministry of Education and Research (01GY2109)
Expected project duration: May 2023 to April 2026
Contact person: Valentina Paucke
Contact: climate@uke.de